1. Field of the Invention
The present invention relates to a method for manufacturing a liquid ejecting head of ejecting a liquid.
2. Description of the Related Art
Examples of a liquid ejecting head of ejecting a liquid, to be used, include an inkjet recording head of ejecting an ink on a recording medium to perform recording. As a conventional method for manufacturing an inkjet recording head, there is a method described in Japanese patent Application Laid-Open No. 2009-178906.
The method for manufacturing an inkjet recording head described in Japanese patent Application Laid-Open No. 2009-178906 will be briefly described. In the method, an antireflective film is first formed on a substrate including an electrothermal conversion element as an energy generating element that generates energy for ejecting a liquid. In this case, SiN is preferably used in the antireflective film, and a SiN film can be formed by plasma CVD, room temperature CVD, or the like. Furthermore, the refractive index n of the SiN film at a wavelength of 633 nm is preferably made within a range of 2.05<n. The SiN film in which the refractive index n at a wavelength of 633 nm is within the above range can further reduce the reflected light from an underlying layer at the time of forming an ink ejecting orifice by i-line exposure, thereby enabling the suppression of deformation of the ink ejecting orifice.
Then, a soluble resin is patterned on the antireflective film to form a liquid channel mold serving as a mold for forming a liquid channel. Then, the liquid channel mold is used as a mask to perform the dry etching of the antireflective film, to thereby leave behind the antireflective film only below the liquid channel mold.
Then, a photosensitive resin layer is formed on the liquid channel mold to thereby form the ink ejecting orifice by photolithography. In this case, reflection from the substrate, occurring upon exposure, is suppressed by the antireflective film, thereby enabling the ejecting orifice to be precisely patterned. Finally, the liquid channel mold is eluted with a solvent to manufacture an inkjet recording head.
In Japanese patent Application Laid-Open No. 2009-178906, the antireflective film is formed as a underlying layer (on the substrate) of a resist to thereby restrain influence of reflected light of exposure on a resist pattern. As the influences given on a resist pattern are known halation and notching, where diffusely reflected light on the substrate affects on the pattern, and a standing wave effect, where reflected light from the substrate interferes with irradiation light from an exposure machine.
However, as in Japanese patent Application Laid-Open No. 2009-178906, when the antireflective film is formed only below the liquid channel, reflection from the substrate may be insufficiently prevented in a recording head having a structure that the distance between the wall of bubbling chamber and the ejecting orifice is shorter, such as a high density arrangement that the width of the liquid channel is narrower. In addition, since the liquid channel mold is used as an etching mask, there may be variation in the height of the liquid channels among etchings.